Harmful Algal Blooms

An algal bloom is the excessive growth and accumulation of one or more species of microscopic single-celled plants called phytoplankton. Phytoplankton are generally beneficial, as they form the basis of the food chain and provide the main source of energy that sustains aquatic life. When unusual conditions exist however, such as when excess nutrients are present (termed eutrophication), a particular phytoplankton species may gain a competitive advantage over others and grow uncontrollably into a nuisance algal bloom. Some blooms involve species that produce potent toxins or have other harmful ecosystem impacts, and may pose health hazards for both humans and other animals. These are referred to by the scientific community as "Harmful Algal Blooms" or HABs.

In recent decades, HABs have increased in frequency and duration around the world, and represent a significant threat to fisheries and public health. An ongoing Suffolk County capital project administered by the SCDHS Office of Ecology, Public Health Related Harmful Algal Blooms (CP-8224), was initiated to determine and monitor the extent to which HABs exist in Suffolk County waters and to assess their potential impact on public health. To meet these goals, the program has provided operational and financial support for numerous scientific research projects in addition to in-house monitoring efforts. A second capital project that is no longer operational, Study for the Occurrence of Brown Tide in Suffolk County Marine Waters (CP-8228), provided critical support to researchers studying the infamous brown tide blooms of the 80’s and 90’s.

HABs that have been documented to occur in Suffolk County waters include the following:

BROWN TIDE - The brown tide is a marine microalgal bloom caused by a species called Aureococcusanophagefferens, that turns waters a light brown color and has been responsible for the decline in eelgrass beds in various locations, as well as the mortality of shellfish, particularly bay scallops. The bloom has appeared in Long Island's Peconic and South Shore estuaries as well as in Narragansett Bay (Rhode Island), Barnegat Bay (New Jersey), Delaware's inland bays, Maryland's coastal bays, and in South Africa. The brown tide was first detected in Suffolk County waters in June of 1985, and has recurred in a number of locations, although unpredictably and in varying degrees of intensity.

In recent years brown tide blooms have been most prevalent in waters extending from eastern Moriches Bay through Quantuck Bay and western Shinnecock Bay, as well as throughout Great South Bay, but have generally been absent in the Peconic Estuary.

The brown tide is a marine microalgal bloom which has appeared in Long Island's Peconic and South Shore estuaries as well as in Narragansett Bay (Rhode Island), Barnegat Bay (New Jersey), Delaware's inland bays, Maryland's coastal bays, and in South Africa. It is caused by a particularly small (2-3 microns in diameter) and previously unknown phytoplankton species called Aureococcus anophagefferens (meaning "golden sphere that causes cessation of feeding").

The brown tide was first detected in Suffolk County waters in June of 1985. Researchers at the University of Rhode Island's Graduate School of Oceanography, using electron microscopy, placed the causative organism in a new genus and species, Aureococcus anophagefferens. The Aureococcus bloom, locally referred to as the "brown tide", has persisted in various Suffolk County embayments (particularly Flanders Bay, West Neck Bay, Quantuck Bay, and in Great South Bay) although unpredictably and with variable intensity.

What are some impacts of the brown tide?

When a brown tide bloom exceeds a concentration of approximately 250,000 cells/ml, affected waters typically turn a murky brown and water transparency decreases to less than 2 feet. This has an immediate aesthetic impact on residents and tourists, in addition to having a serious impact on eelgrass (Zostera marina) beds due to reduced light penetration. Eelgrass is actually a flowering plant that requires light to manufacture its food (through photosynthesis). Eelgrass beds are an extremely important component of marine ecosystems, because they provide spawning and nursery grounds for fish and shellfish and play a critical role in estuarine food webs.

Perhaps one of the most severe impacts of the brown tide has been on the Peconic Bay scallop industry. This resource, once estimated to be worth more than $2 million dollars annually, was virtually eradicated by the brown tide. Attempts to revive the industry through seeding operations have been marginally successful. Although the last major brown tide bloom in the Peconic Estuary occurred in 1995, the bay scallop harvest has still not recovered to levels that existed prior to the 1985 bloom.

Other shellfish species, including hard clams, oysters, and mussels have also been seriously affected. Declines in finfish landings are an additional impact, as fish seem to avoid bloom areas.

Does the brown tide pose a public health threat?

Although the brown tide has had a serious effect on natural resources, the local economy, and the general aesthetic value of the estuaries, it is not known to be harmful to humans. Although reduced water transparency may present certain safety risks to bathers, there is no evidence that either consuming finfish or shellfish from affected waters, ingesting the brown tide, or bathing in water containing brown tide, has any harmful effects.

What causes brown tide blooms?

Although advances have been made regarding the identification and characterization of the brown tide organism and its growth needs, the causes of brown tide are still not clear. The input of conventional inorganic nitrogen and phosphorus nutrients (ammonia, nitrate, and phosphate) apparently do not trigger the onset of the blooms, although the availability of organic nitrogen compounds may play a role. In the Peconic Estuary, groundwater inputs affecting the relative amounts of dissolved inorganic and organic nitrogen may be an important factor in the onset of brown tide blooms.

Other factors identified as having potential involvement in the growth and predominance of brown tide include the following:

chelators such as citric acid and trace metals such as iron, selenium, vanadate, arsenate, and boron

the failure of potential grazers (microzooplankton) to keep brown tide in check

meteorological and climatological factors - it has been postulated that reduced flushing due to a change in wind induced subtidal sea level oscillation, results in the retention of land-derived nutrients that may stimulate brown tide blooms

physio-chemical limits - monitoring data collected by the Suffolk County Dep't. of Health Services suggest that salinities in excess of 26 parts per thousand and temperatures between 20-25 degrees C may be factors associated with the occurrence of major blooms

the presence of filter feeding clams that may play a role in limiting bloom development

in low light conditions (typical of the turbid Great South Bay) the organism can supplement photosynthesis with the uptake of organic compounds, giving it a competitive advantage over other phytoplankton species

As part of the county's ongoing response to the "brown tide" problem, the Brown Tide Comprehensive Assessment and Management Program (BTCAMP) was initiated in 1988. The program's objectives were not only to research the causes and impacts of the brown tide, but to investigate more conventional water quality problems affecting local embayments so that corrective actions to minimize them could be identified and evaluated. The BTCAMP study concentrated on the Peconic Estuary System, although other marine waters where the brown tide had occurred, including Shinnecock Bay, Moriches Bay, and Great South Bay, were also occasionally examined.

The final management plan was supported by a comprehensive series of tasks including monitoring of the bays, assessment of the sources of pollutant loading to the bays (e.g., stormwater runoff, sewage treatment plants, groundwater inflow), analysis of land use in the area surrounding the bays, and computer modeling of water movement and quality in the bays.

What were some of the findings of the BTCAMP study?

Briefly, BTCAMP found that although all algal growth requires nitrogen and phosphorus macronutrients, the brown tide is apparently not triggered specifically by them. The study suggested that the brown tide may have been caused by other factors including meteorological patterns and specific chemicals (organic nutrients, chelators, and certain metals), and recommended further laboratory and field research in these areas in addition to investigating factors related to brown tide subsidence (viruses, zooplankton grazing) and brown tide impacts on shellfish.

Are any reports or water quality data available for downloading?

To access the BTCAMP summary document, or to download water quality monitoring data, contact the department.

RED TIDE – Red tides are generally caused by a class of phytoplankton called Dinoflagellates, which, under bloom conditions, can discolor effected waters red. Not all red tides are harmful, although those that produce biotoxins can be lethal to fish and shellfish and potentially pose serious public health threats.

The red tide caused by the organism Alexandrium, is associated with an illness known as Paralytic Shellfish Poisoning (PSP) that results from the ingestion of shellfish contaminated with a potent toxin that these algae produce. When concentrated by consuming shellfish, this biotoxin (called saxitoxin) can result in levels that are lethal to humans. Symptoms of PSP will depend on the amount of toxin ingested, and can progress from tingling of the lips and tongue, to numbness of the face, neck and limbs, loss of muscular control, followed by difficulty breathing.

Previous investigations conducted by the Office of Ecology (1986-1989 and 2000-2001) found Alexandrium (and measureable levels of saxitoxin) in various Suffolk County embayments, although no cases of paralytic shellfish poisoning were documented. More recent monitoring conducted by the NYSDEC has noted almost annual blooms in the Huntington-Northport Bay complex (2006, 2008-2012), resulting in precautionary shellfish bed closures. In 2012, PSP was also detected in Shinnecock Bay, Mattituck Inlet and Sag Harbor Cove.

In the northeastern United States, paralytic shellfish poisoning (PSP) is an illness caused by eating shellfish contaminated with a dinoflagellate marine algae (Alexandrium) that contains a powerful biotoxin called saxitoxin.

Is paralytic shellfish poisoning (PSP) caused by "red tides"?

“Red tide” is a reference to the reddish brown discoloration that is imparted to the water column by an algal bloom, and is typically associated with one of many dinoflagellate species. In New York and New England waters, Alexandrium is a dinoflagellate that causes red tides, and is the principal organism associated with PSP. However, it is not necessary for a red tide to be present for shellfish to be contaminated with PSP. Bivalve mollusks, including clams, mussels, scallops, and oysters, gather their food by filtering algae and other plankton from the water. Because this causes the algae to become concentrated in their systems over time, the mollusks can be poisonous even when there is insufficient numbers of dinoflagellates present to cause a visible red tide.

What are some symptoms of PSP?

Symptoms of PSP will depend on the amount of toxin ingested, and can progress from tingling of the lips and tongue, to numbness of the face, neck and limbs, loss of muscular control, followed by difficulty breathing.

Has PSP been found in Suffolk County waters?

Primarily, PSP is associated with shellfish taken from waters north of Long Island, including those of Maine, Massachusetts, and Connecticut. Previous investigations done in Suffolk County waters however, have found Alexandrium to be present although no cases of paralytic shellfish poisoning have been documented. Studies done by Anderson et al. (1982) revealed the presence of Alexandrium cysts in the sediments of 6 of 31 Long Island estuaries examined. Schrey et al. (1984) found vegetative cells in 46 of 115 Long Island estuaries and inlets sampled during the spring of 1983. The toxin content of cell cultures grown from the cysts found by Anderson et al. however, was low. This agreed with a study done by Miranda et al. (1985) who noted that the toxin content of Alexandrium isolates along the east coast decreased from north to south.

More recently, studies conducted by the NYSDEC have noted almost annual Alexandrium blooms in the Huntington-Northport Bay complex (2006, 2008-2012) that all resulted in shellfish bed closures due to presence of the toxin. In 2012, PSP was also detected in Shinnecock Bay, Mattituck Inlet and Sag Harbor Cove.

Does Suffolk County monitor local waters for PSP?

In response to the early findings mentioned above, a survey was undertaken by the Office of Ecology from 1986 through 1989 in an effort to characterize the population dynamics of Alexandrium in eleven Suffolk County embayments, and coincidentally, determine the levels of PSP toxin present (by mouse bioassay) in mussels placed at each site (Nuzzi and Waters, 1989). Of the eleven sites studied, PSP toxin was only found in mussels placed at three sites in the western Peconic Estuary (Reeves Bay, Terrys Creek, and East Creek). The public health standard of 80 ug of toxin/100 g of shellfish meat was exceeded on one occasion.

In the spring of 2000, a second PSP survey was initiated by the Office of Ecology that involved the monitoring of nine sites in the Peconic Estuary (including the Peconic River, Reeves Bay, Terrys Creek, Meetinghouse Creek, East Creek, James Creek, Deep Hole Creek, Cold Spring Pond, and Bullhead Bay). Sampling was repeated in the fall at the same locations; results for all samples collected were negative. During 2001, the survey was performed at locations in Shinnecock Bay, and Moriches Bay including Weesuck Creek, Quantuck Creek, Beaverdam Creek, Seatuck Cove, Hart Cove, and the Forge River. Positive results were found at all locations in the spring (but not the fall), although the levels of toxin detected were well below health standards.

As the NYSDEC has now developed their own PSP program, Suffolk County no longer conducts routine monitoring for the organism.

Where can I find more information on PSP?

For more information, visit any of the links below or contact the Office of Ecology at (631) 852-5760.

References

Nuzzi, R, and Waters, R.M. 1993. The Occurrence of PSP Toxin in Long Island, New York, USA. Toxic Phytoplankton Blooms in the Sea. pp. 305-310.[Upload Pending]

RUST TIDE – The rust tide is a relatively new (to Suffolk County) “red tide” caused by the organism Cochlodinium polykrikoides. Since 2004, this HAB has recurred throughout the Peconic Estuary, including in Flanders Bay, Great Peconic Bay, West Neck Bay, and Coecles Harbor, as well as in eastern Shinnecock Bay. In 2011, the organism was also observed in Great South Bay.

During the widespread blooms of 2008 and 2009, fishermen reported the mass mortality of fish held in pound nets both in the Peconic Estuary and in Shinnecock Bay. During 2009, a mass mortality of scallops that occurred in Little Peconic Bay and Noyack Bay was likewise attributed to a bloom of Cochlodinium polykrikoides.

Studies conducted by Dr. Chris Gobler of the School of Martine and Atmospheric Sciences of Stony Brook University, and funded by Suffolk County Capital Project 8224 (Harmful Algal Blooms), have demonstrated that this organism can have a serious impact on marine resources, as it is capable of killing other phytoplankton, zooplankton and fish, as well as juvenile and larval shellfish including bay scallops, hard clams and oysters, in a matter of hours to days.

Cochlodinium polykrikoides (C. poly) is an emerging “red tide” HAB first noted in Suffolk County waters in 2004. It causes intense and widespread reddish-brown blooms that have been coined locally as the “rust tide”. The organism has been implicated as causing toxic algal blooms in coastal waters worldwide (Gobler, 2010), and has been found to be lethal to multiple species and life stages of fish and shellfish. Locally, the initial bloom occurred throughout the Peconic Estuary and in eastern Shinnecock Bay in 2004, and has occurred at the same locations every year since (through 2012). In 2011, blooms also occurred in Great South Bay.

Studies conducted by the School of Marine and Atmospheric Sciences of Stony Brook University, and funded by Suffolk County Capital Project 8224, Harmful Algal Blooms (Gobler, 2010), have demonstrated that the organism is highly toxic, capable of killing other phytoplankton, zooplankton and fish, as well as juvenile and larval shellfish including bay scallops, hard clams and oysters, in a matter of hours to days. Observed impacts during blooms have included the complete mortality of captive finfish and the mortality of caged and wild shellfish. During the blooms of 2008 and 2009, fishermen reported the mass mortality of fish held in pound nets both in the Peconic Estuary and in Shinnecock Bay. During 2009, a mass mortality of scallops that occurred in Little Peconic Bay and Noyack Bay was similarly attributed to a bloom of Cochlodinium polykrikoides .

Studies have also demonstrated the organism to be nutritionally flexible, capable of assimilating a variety of nitrogen compounds, thereby giving it a distinct competitive advantage over other algal species. Recent work by Gobler confirmed the production of resting cysts by C. polykrikoides in laboratory cultures, providing a mechanism that accounts for the recurrence of annual blooms in specific embayments as well as the expansion of blooms across the county (Gobler, 2013).

DINOPHYSIS – An illness known as Diarrhetic Shellfish Poisoning (DSP) is caused by the ingestion of shellfish that have been feeding on blooms of Dinophysis acuminata, a Dinoflagellate organism that produces the biotoxin Okadaic acid. In 2011, a Dinophysis bloom in Northport Harbor caused the first documented DSP event in Suffolk County. Recently, blooms have been documented in Meetinghouse Creek in the western Peconic Estuary.

CYANOBACTERIA - Cyanobacteria, also known as blue-green algae, are microscopic organisms found in both marine and fresh water environments. They are usually present in low numbers, but under favorable conditions of sunlight, temperature, and nutrient concentrations, can form massive blooms that discolor the water and often result in a scums and floating mats on the water’s surface. Some species of cyanobacteria produce toxins that can cause health problems in humans and animals if exposed to large enough quantities.

Past studies have documented cyanobacteria blooms in a number of freshwater systems in Suffolk County, including some that contain public bathing beaches. A twenty lake survey conducted in 2004 by Stony Brook University, and funded by Suffolk County Capital Project 8224 (Harmful Algal Blooms) found that all of the lakes studied contained potentially toxic cyanobacteria and detectable levels of the toxin microcystin. Fifteen of the lakes showed toxin levels exceeding World Health Organization (WHO) levels permissible for drinking water, with five lakes having levels that posed a moderate–to-high risk to human health for recreation. One of the latter five sites is a very popular bathing beach on Lake Ronkonkoma.

Follow-up studies have found have found nearly annual blooms in some lakes (Lake Agawam and Mill Pond in Southampton), with periodic blooms occurring in other systems, some of which include bathing beaches (Lake Ronkonkoma, Deep Pond - Schiff Scout Camp, and Great Pond – Peconic Dunes Camp). The blooms in Lake Ronkonkoma in 2009 and 2013 were of a magnitude that warranted immediate closure of the lake’s bathing beaches.

Cyanobacteria, also known as blue-green algae, are microscopic organisms found in marine and fresh water environments. They are usually present in low numbers, but under favorable conditions of sunlight, temperature, and nutrient concentrations, can form massive blooms that discolor the water and often result in a scums and floating mats on the water’s surface. Some species of cyanobacteria produce toxins that can cause health problems in humans and animals if exposed to large enough quantities.

Frequently Asked Questions

Are all Cyanobacteria toxic?

No. There are many species of Cyanobacteria, many of which are non-toxic. Moreover, species that are known to be toxic may only be toxic at certain times within a bloom when environmental conditions are optimal.

What are typical routes of exposure to Cyanobacteria?

People can be exposed to cyanobacteria and cyanotoxins by swallowing the water, by skin contact with the water and/or the surface scum, or when airborne droplets containing toxins are inhaled while swimming.

What are the human health risks associated with exposure to Cyanobacteria?

Any reaction to cyanobacteria exposure will depend on the type of species and toxin present, the toxin concentration, and the duration of the exposure. The higher the concentration of cyanobacteria and toxin and the longer the contact with the water, the more severe the symptoms may be. Health effects typically occur only when exposed to high levels of cyanobacteria and/or their toxins, although some people may be sensitive to lower levels.

Skin contact with the organisms can cause irritation of the skin (rash or skin blisters), eyes, nose and throat, and inflammation of the respiratory tract. Swallowing water containing high levels of toxin can lead to nausea, vomiting, abdominal pain and diarrhea. Effects on the liver and nervous system of animals and people have also been documented in severe cases. Livestock and pet deaths have occurred after these animals consumed large amounts of algal scum that had accumulated along shorelines.

Are some individuals more at risk?

Yes. Children and individuals with liver disease, kidney damage, or weakened immune systems may be at greater risk. Children have a greater opportunity for exposure to Cyanobacteria blooms, since they tend to be curious and may explore the shoreline of a lake. Because children tend to swallow a greater volume of water per body weight than adults, they also have a greater potential risk from exposures to blooms.

How can you tell if waters contain Cyanobacteria?

People should suspect that blue-green algae could be present in water that is visibly discolored or that has surface scums. Colors can include shades of green, blue-green, yellow, brown or red. Water affected by blue-green algal blooms may also develop a paint-like appearance. Contact with waters that appear scummy, turbid or discolored, should be avoided.

What should I do if I think I swam in waters containing Cyanobacteria?

The first step is to wash with warm soapy water. Remove clothing to avoid contact with trapped algal cells, as these may cause skin irritations. If any of the above exposure symptoms develop, contact your physician immediately. In any event, please alert the Suffolk County Department of Health Services at (631) 852-5760.

What should I do if I think I my pet entered waters containing Cyanobacteria?

Wash your pet with warm soapy water, and if any of the above exposure symptoms occur, contact your Veterinarian. Also, please alert the Suffolk County Department of Health Services at (631)-852-5760.

PFIESTERIA - Pfiesteriapiscicida is a toxic dinoflagellate that has been implicated in recent years in causing fish kills in brackish coastal waters from North Carolina to Delaware. The organism has a complex life cycle that includes numerous different morphological forms, some of which produce toxins. Sampling conducted from 1998-2004 documented the presence of Pfiesteria in a number of Suffolk County embayments. Although the organism was found to be widespread, the colder waters characteristic of Long Island are not thought to be optimal for bloom formation and thus toxin production. With the onset of climate change however, this may need to be re-evaluated.

Pfiesteriapiscicida is a toxic dinoflagellate (a type of phytoplankton or microalgae) that has been implicated in recent years in causing fish kills in brackish coastal waters from North Carolina to Delaware. The organism has a complex life cycle that includes numerous different morphological forms, some of which produce toxins. Sampling done from 1998-2004 documented the presence of Pfiesteria in a number of Suffolk County embayments.

What causes Pfiesteria to grow and become toxic?

The conditions that result in toxin production by Pfiesteria, although not well understood, include the presence of large schools of fish, warm temperatures, brackish salinity, poorly flushed waters, and high nutrient (nitrogen and phosphorus) concentrations.

Does Pfiesteria have any public health effects?

Preliminary investigations suggest that exposure to waters where toxic forms of the organism are present may also cause human health effects, including headache, nausea, skin irritation, difficulty breathing, memory loss and confusion.

Is monitoring currently being done to test for Pfiesteria in Suffolk County?

In an attempt to provide a more complete picture of the organism’s distribution and temporal variations in Suffolk county waters, the Office of Ecology conducted a Pfiesteria monitoring program from 1998-2004. Samples were collected during summer months at 62 sites around the county and forwarded to the University of North Carolina for analysis.

Results of the study found Pfiesteria to be relatively common in Suffolk County waters, although no blooms were observed and evidence of Pfiesteria-related fish or human health problems was not apparent. These results were in agreement with other studies that suggested the colder temperatures of Long Island waters are not optimal for Pfiesteria bloom formation and toxin production. With this in mind, subsequent monitoring has not been conducted.

Where can I get more information on Pfiesteria?

For more information on Pfiesteria, visit any of the links below or contact the Office of Ecology at (631) 852-5760.